Usually, an illumination window or illumination windows and an optical observation window are provided on a rigid tip end section at the distal end of an endoscopic insertion member or rod. In order to wash smudged observation window, an observation window washer means is normally provided on an endoscope thereby to feed wash air and liquid for cleaning purposes. The observation window washer means is constituted by a wash fluid passage which is connectible to a jet nozzle located in the vicinity of an observation window. A wash fluid passage of this sort is passed through a universal connection cable which is extended out from a manipulating head assembly of the endoscope, to which a proximal end of an endoscopic insertion member is connected. The wash fluid passage is led out from a connector which is provided at the fore distal end of the universal connection cable. From a jet nozzle, a wash liquid is spurted out toward the observation window along with compressed air. For this purpose, the observation window washer means is provided with a liquid feed tank as a wash fluid source, and an air pump. A control valve is mounted on the manipulating head assembly of the endoscope, and the control valve is manipulated by a finger of an operator to trigger jets of wash liquid and blasts of compressed air toward the observation window.
The above-mentioned endoscopic observation window washer means constitutes an endoscopic fluid feed system, and may include a fluid injection means in some cases. In the endoscopic observation window washer means, which is intended to supply a wash liquid and/or compressed air toward surfaces of an endoscopic observation window, a wash fluid feed passage which is provided axially and internally of an endoscopic insertion member is arranged to turn a fluid flow direction substantially at right angles relative to the longitudinal axis of the insertion member on introduction into a jet nozzle. In contrast, a fluid injection means is primarily resorted to at the time of washing an intracavitary site with jets of a wash fluid. Namely, a fluid injection means is resorted to primarily for the purpose of washing away contaminants from an endoscopic observation site with jets of a wash liquid under high pressure because deposition of blood or other body fluids or solid contaminants on an intracavitary site under observation would considerably hinder visibility of an intracavitary side under observation through an endoscopic observation window on a rigid tip end section of an endoscopic insertion member. A fluid injection means is also used for injection of a coloring agent or a medicinal liquid. Thus, normally a fluid injection means is adapted to spurt a jet of liquid forward in the direction of longitudinal axis of an endoscopic insertion member.
A fluid injection means is opened in an end face of a rigid tip end section, at a terminal end of an injection passage to which a fluid feed conduit from a fluid supply source is disconnectibly connected. Therefore, an injection passage is extended internally and axially through an elongated insertion member at least as far as a manipulating head assembly of an endoscope. In some cases, both an injection passage and a fluid feed conduit are provided on a manipulating head assembly of an endoscope. In such a case, however, an external conduit which is connected to the manipulating head assembly can hinder manipulations of the endoscope. Further, there has been known an endoscope having an injection passage extended internally of a universal connection cable. In this regard, it has been known in the art to connect a fluid feed conduit disconnectibly to a connection port on a connector which is attached to a distal end of a universal connection cable for connecting the endoscope to an external light source and other external components, for example, as shown in Patent Literature 1 below.
Prior Art Patent Literature
[Patent Literature 1] Japanese Laid-Open Patent Application 2003-33320.